When I don't understand some grammar,I always watch videos on YouTube.As I watch many videos,I'm understanding more and more about English.To my knowledge, English,my favorite subject, is not same as other languages.It has many exceptions.
I know I will pay off one day as long as I go on learning.I want to have an excellent grasp of English.

Does this paragraph natural?

Question

When I don't understand some grammar,I always watch videos on YouTube.As I watch many videos,I'm understanding more and more about English.To my knowledge, English,my favorite subject, is not same as other languages.It has many exceptions.
I know I will pay off one day as long as I go on learning.I want to have an excellent grasp of English.

Does this paragraph natural?

Answer

Basically, this sounds very natural, Ei Shwe Zin. Well done! 👍.

Here are a few suggestions for improvements:

"When I don't understand 'a grammar point'..." (Although you could say "some grammar")

"English... is not 'the' same as other languages..."

"I know 'my efforts' will pay off one day..."

Answer

Also, we put spaces after each punctuation mark.

Below is a correction of the first 2 sentences:

When I don't understand some grammar, I always watch videos on YouTube. As I watch videos, I understand more about English.